Fuse switch



July 27, 1943.

R. R. PI'ETMAN ErAL FUSE SWITCH Filed Jan. 12, 1939 2 Sheets-Sheet 1 INVENTORS July 21, 194s. R. R. PITTMAN ETAL FUSE SWITCH Filed Jan. 12, 1939 2 Sheets-Sheet 2 2 1 mvzmoas W fvivsbu Patented July 27, 1943 T OFFICE & FUSE swrron Ralph R. Pittman and Carroll H. Walsh, Pine Bluif, Ark.

Application January 12, 1939, Serial No. 250,603

v 18- Claims.

This invention relates generally to fusible switching devices, such as fusible circuit interrupters or fuse switches, used for the purpose of disconnecting anjelectrical circuit upon the attainment of a predetermined current therein.

Among the objects of the present invention may be noted: (a) the provision of means for d sconnecting certain normallyalive elements of the fuse switch while the connecting member is many ually held in the closed position; (e) the provision of a switch embodying a contact member, and means for limiting the movement of the contact member; (f) the provision of an actuating elementnormally restrained by a tensioned fuse link and a contact arranged to be actuated in response to movement of the actuating element, the elem'ents being so related and arranged that the actuate'd contact is held in a circuit closing position independent of thetension of the fuse link; (9) the provision of means for delaying the move ment of the contact until the separated portions of the fuse link following its fusing are'mechanically separated for a substantial'distance; and (h)- guide meansfor directing the'pat h'of movement of the connecting member toposition.

As may be noted from the objects above stated, our fuse switch embodies several improvements not foundindevices of this character which are now available. Present switches which embody means-for disconnecting the fuse tube in response to the rupture of the fuse link are generally of a when the fuse link fuses. In such constructions.

the tension to which the fuse link is subjected is a function of the contact pressure when the fuse tube in the closed position. This organization' has the inherent difficulty 1 of a fuse link tension which varies directly with the contact pressure; The desired arrangementis one in the closed which there is a high contact pressure and a low fuse link tension. Our invention is an arrangement in which the fuse link tension is entirely independent of the contact pressure. In addition, the dropping-out of the fuseswitchis undesirable, as it results in an inverted tube when the latter is in the open position, which mayfill with rain water and be damaged thereby. In the presexit-invention, the fuse tube remains unmoved, and in the closed position, but at the same time is effectively open-circuited in re ponse to the blowing of the fuse link. A further advantage in the present invention, not found in prior structures, is in the arrangement in which the opencircuiting of the device is independent of the manual operation of the switch; that is, the" fuse tube'cannot be manually held so that it will remain inthe circuit if the fuse link is ruptured by blowing. In other words, our fuse switch is tripfree'of the manipulating eye.

' Other advantages and objects will be apparent from the following description andclaims, taken in connection with the accompanying drawingsforming a part of this application, in which:

Fig. '1 is a side elevational view of the switchshown in the closed circuit position.

Fig. 2 is a fragmentary section taken along the 1ine IfII of Fig. 1.

Fig. 3' is a fragmentary side elevation showing the position of the lower elements of the switch immediately following the fusing of the fuse link.

Fig, 4 is another fragmentary side elevational view, illustrated partly in section, and showing the final position taken by the lower elements of the switch following the rupture of the fuse link.

Fig. 5 illustrates, partly in section, the connee-ting member of the switch, in the open or inverted position, as after manual manipulation preparatory to re-fusing the switch.

Fig. 6 is a fragmentary front View, with the fuse tube broken away to better illustrate the do ments. Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Referring more in detail to the drawings, it may be. seen that our fuse switch may be conveniently divided, for purposes of description, into two parts; the first being-the substantially stationary or fixed-members, includingthe fixed terminals', and the second being the connecting member which is movable and removable with respect to the fixed members.

The first part'includes the longitudinally extending-insulator i l, of porcelain or other suitable insulating material, which is arranged to extending upper terminal support I2, in any suitable manner, and a line connecting terminal l4 necting terminal-i3. A fuse link 3|, fastened at its upper end to the upper contact 50 of the tube provides means for electrically connecting the line conductor E5 to the upper terminal l3.

A fuse assembly or connecting member support it encircles the lower end of theinsulator l8, and;

is rigidly secured thereto by the bolt and nut I8. The end portions of the member is extend outwardly in the same direction as that of the upper terminal support 12, being held in substantially parallel relationship one to the other by the spacer l7, and at the outer ends are provided with a pairof'hooks 3-and 44. Anoutwardly extending load terminal l9,' of resilient conducting material, encircles the insulator Ill at a position in spaced relationshipwith the bracket 1 l and the supporting member l5, and is rigidly secured to the insulator If) between the latter members. The load or lower terminal i9 is preferably in the form of two parallel substantially horizontal outstanding arms, as shown in Fig. 6, being held in parallel relation by means of the load terminal clip 20. A load connecting terminal 2| provides means for electrically 'connecting the load conductor 22 to the load terminal [9. From the above description, it may be seen that the upper terminal support l2, the bracket II, the load terminal I9,'and the supporting member it are all mounted on the insulator H3 in insulated spaced relationship to each other. 1

The movable and removable connecting member or fuse assemblyof the switch includes a hollow tube of insulating material 23, to the lower end of which-is rigidly secured, by means of the 23 by the screw plug i2, normally extends downwardly through the tube 23, and has its lower end fastened to the fuse link terminal member 32 by means of the fuse link connecting member 33, so that, under the normal condition with the fuse link unfused, the downwardly extending portion of the fuse link terminal member 32 lies along and close to thelower end of the fuse tube 23. A tension spring 58, having one end attached to an upwardly extending portion 35 of the fuse link terminal member 32, and the other end to the'eye portion 28 of the fuse tube support 26 continually urges the fuse link terminal member 32 in a direction to tension the fuse link 3!, and

' also to rotate the lower portion of the fuse link set screw 25, a fuse tube support 24. The latter" encompasses the lower end of the tube 23, andis provided with a pair of oppqsitely extending pintles 25 and 21, arranged to seat or rest in the hooks 43 and 44 respectively, and thereby pivotally support the connecting member at its lower end. A pair of outwardly extending portions 3!] extend upwardly from the pintles 26 and 21, as shown in Fig; 4,- and arearranged to frictionally engage the innersurface of the hooks 43land 44, and thereby guide the rotative 'moveposition, the eyes All and 28 are'integrally formedv on the members 49 and 24 respectively.

An integral upwardly extending portion 29 of the fuse support 24 is positioned between the fuse tube 23 and theinsu ator ill, and below'the terminal l9, and provided witha, horizontally extending opening through which the, pivot 39' passes, as shown i'n Figs. 2 and 6. A bifurcated fuse link terminal member 32 is mounted on the pivot 39 for rotation thereabout, and extends first across the tube 23, and thencedownwardly therealong to the lower end thereof, being provided at the lower end with the fuse link conterminal member 32 away from the fuse tube A bifurcated load or lower terminal-engaging contact 34 is also mounted on the pivot 39 for pivotal movement in the-same direction as that of the fuse link terminal member 32, the contact 34 extending upwardly from its pivotal mounting to engagement with the terminal Land being so positioned and formed that the direction sure on the connecting member is between the pintles 26 and 21 and the insulator 58, or so as totend to rotatethe entire fuse tube assembly in a counterclockwise direction about the pintles.

This arrangement maintains the connecting member in the closed position when the fuse link is unfused,-and' makes unnecessary any latching device for holding the upper end of the fuse tube in the proper position.

With the connecting memberin the norma closed position, and with the fuse link unfused, it may be seen that a series circuit is provided through the switch from the line terminal :3 to the fuse link 3!, thence through the latter to the fuse link terminal member 32, thence I through the latter to the lower terminal contact member 34, and thence through the latter to the lower terminal I9. Under the above stated conditions, the elements of the switch occupy the,

positions illustrated in Fig. 1. It will now be apparent that the fuse link 3! is tensioned by the spring 38, butthatthe portion of the lower surface 45 of the contact 34 which lies in the path of movement of' the portion 55 of the fuse link terminal member 32 is spaced from the latter,

so that no forcetending to move the contact 34 is impressed thereon by the spring 38; that is, the movable contact member is held in the closed position independent of the tensioned fuse link.

Once in the normally closed. circuit-position, as above stated, the contact member 3 is maintained in the closedposition independent of the tension of the fuse link 3i; however, it is necessary. to provide means for positioning the contact member to accomplish this result whenv the connecting'member is moved from the open position shown in Fig. 5, to the closed position'shown in .Fig. 1. For this purpose, an integral bar 35, joining the legs of the bifurcated contact member 34' at their respective. lower ends, is arranged to limit the movement of the contact 3 in a mam.

clockwisadlnectiom by engaging a pontiomoithe; tube support 2d,,and thmoounterclockwise more. mentisx limited by the engagementoilt-he sloping; portions 31*: of 1318* contactimemberv 34 withithetop surfaces of the; laterally oxtendiugganme of. the fuse link terminal; member 32:1.

Assume-now: that the switch. is; im the: closed. circuit; position illustrated. hand: that. the-fusible element P'OfthEfllSQ'liBk' 3:4: is; fused; by an abnormal current in thc:cincuit.. Upon: the parting of. the. fuse-link. Hi the'z fuse link barf-- minal': member: 32' is: no longer held: by the fiLlSB link 3b, and1is rotated;- abounthe-asis ofi the pivot 33;; undeniable: influences ofi the: spring; 38% until; theimpacting: portion 4% reaiches in its path: of. movement, the'gortion'. 4510f. contact- Mr Fig: 3-. illustrates; the; DGSitilOIll of the: elements at this stage; that is, iust, prior to; striking: the: contact. member. 34?. Itshouldibe noted that, asthmfuse: link termini-11' member rotates; the lower end: on the fuse linlr. 3 is. extrantedi from'the: tube. 23;, This assures: that; the cincuitrinterrupiiing arc: will be: extinguished bBfOIBLthBGOIltflCt 31.: is. struck. It may also'bei noted'that-mefusealinih terminal; member.- travels; over an before impact. occurs; thereby: acquiring" substenz tial momentumzbefore theiinstant ouimpzacti.

Following impact, the: elements: assume the. positions. indicatedin 41;. The terminah con:- tact member 34 havindbeern strucl: by 'theo fuse: link terminal member 32;.hnssbeerr d-l'lizem disengaged position: with respect to the: loud GEE-- min'al I9 'Ih'es.portilmv ofi'the: msulator lifllbez 'tween'the' terrriinzvalla and thesupport litismoxv electrically interposed in series circuitt'relaztioni withihe fuse tube Ntthc fuse link: the support" lb and the upper terminal v k3,.pmvidingrsa" definite open: circuit, or. disccnnectioni of: these members. from the load terminafi it; The fuse: terminalmember. 3:2 hESFHIUVQdLlZHdEf the: bias of the spring 38 so: that its; IUWEIlTDUDfibIISZ new ext-end outwardly away'fromitlie tube, thum providing: an easily visible? indicatiem that; the: fuse-link heal-used,v andrth'at the has. actuate d the: closed: circuit: UH? the: opem circuitposition:v I

To re-fuse the switch, the eye.- 41+: is; moved; outwardly and. downwardlwur rotate the. com nesting member; on the: pint-lesrZ 9: and: 21 ,ito. the

inverted nositionsho-wir in-Fig..5;. l he sssembly may then, be liftedcutzof the hooks; 43: and: M;- It Will: be'scerrthat both-tenninals ofi-theeswiiich: are disconnectedfromthe: connecting: member when itis in the rosit-ion shown by'Elgz. 5, whixzh:

desirable fromthe standpoint of safety to; tho:-

position. in series: with: the circuit i'fithefilse' link has'blown;

While We have shownandiriescrib'edl he specific embodiment of our invention; it 'wiil be understood that this: has been! done? to better illustrate its-iconstruction andoperati'on; and that our invention to be limitedtonly' as maybenecessitatcd. by the prior art and appended claims: 1

v\"l'erclaim as; our invention;

1.. A false:- switch; comprising an. insulator; spaced; switch: terminals supported. thereou,.. a fuse tubezmountedrorn said.insulator;v a. fuse: link temnina-limemben'pivoiially'mountedi 011 said tube at; GDGETSidEZ thereof, said. fuse: linkiterminat mem. heir spanning? said. tube; and extending: dbwnwmdlymlong theilatter' to: a; point adjacent. the luwerremizofi' said: tube. a. fuse. link; extending thmughi said tube and secured: to said? fuse. link ternzinal' member atits lower end and on the sideof: the: tube: opposite the. pivotal' mounting of. said tuselinir terminali member; a load terminaitcontact'. member pivoted. on said tube and engaged with one switch terminal; meansi'ncludi'ng thez-serl'ab arrangement-of: said fuse link, said mum: terminal lmember' and said l'oad termmzl'aontact member for electrically connecting said switch terminals and means responsive to ruptureofi said fuse link fordi'sengagi'ng'said load terminal contact member from saidon switch terminal;

2.-In'- a) fuse switch; spaced terminals; means supporting" afuse tube in seriescircuit" relation with said terminals; afiiselink terminal member ancf a= tenninal'engagihgcontact member pivotallymounted'on said fuse tube for rotation about a. common axis; a-fuseIlnkwithin said-tubehavih'g" one end fastened thereto and the other end fastened to-said fuseli'nk terminal member, and resilient means urging said fuse link terminal member-inadirection to tension said fuse link, said terminal engaging contact member having air-portion thereofpositioned inthe-path of movement of said fuse'll'nk' terminal member; the arrangement being such that said terminal? engaging contact; member is struck a blowfbllowing a; predetermined movement of saidfuse llnlk terminal member which occurs without movement of said contact member and thereby disengaged iron the terminal upon rupture of said fuse-link;

a. fuse switch, spaced terminals-, a fuse tube: a--'swingably movable fuselink terminal member at'the lower-end of said tube, a swing-- ably movable load contact member positioned inthe pathof movement of said fuse link terminal member and arranged tobe engaged by the latter after its movement for apredetermined distance alongsaid path while saidcontact member remainsunmoved resilient means urging said fuse llh'l terminal member in a direction to engage said Toad contact member, and means including a= fuse link extending through said tube e1ec-- trically connectingsaid'terminals, said fuse link" being fastened to-saidf-use link terminal member and restraining the movement" thereof.

4 In a'fuse switch, spaced terminals; a fuse tube,- a'" swihgably movable fuselink terminal member'and a: swingabl y movable terminal con tactmember pivotallymounted at tl'ie' lovver"end of saidtube for rotation about a common'axis, said-terminal contact member having a portion thereofi'interposed inthe-path of'movement' of said fuse link terminal member, resilient means urging sai'dfuselink' terminal member in a directi'on to'st'rike and initiate movement of said ter-- minal contact memberonly after said fuse link terminal member has moved for a" predetermined distance, andmeans including a fuse link ex-- tending through said fuse tube electrically connecting said terminals, said fuse link being fastimed to said fuse linktermi'nal member" and normally restraining the movement thereof;

51 A- fuse switch: comprising. aninsulator;

spaced terminals supported thereon, a fixed fuse tube mounted on said-insulatona swingably-movable fuse link terminal member: and a swingably movable terminal-engaging contact member pivotally mounted on said fuse tube at the lower end thereof for rotation about a common axis, said terminal-engaging contact member normally engagingone terminal of the terminals and havinga portion thereof interposed in the path of movement of said fuse link terminal member; resilient means'urging said fuse link terminal member so as to-strike and initiate movement of said contact member in a direction to disengage the latter from said one'terminal only after said fuse link terminal member has moved'for a predetermined distance, and means including a fuse link extending through said fuse tube electrically [connecting said terminals, said fuse link being fastened to said fuse link terminal member and normally restraining themovement thereof.

6. In a fuse switch, insulatingmeans supporting relatively spaced terminals including'an outwardly extending lower terminal of resilient conducting material, a connecting member movable between open and closed positions, said 'connectment of said fuse linkterminal member-for engagement by'the latter after it has moved a predetermined distance alongsaid path,means biasingsaid fuse link terminal so as to engage and initiate-movement of said contact member away from said outwardly extending lower terminalonly after said fuse link terminal member has moved over said predetermined distance, and means including a 'fuse link v extending through said tube and electricallyconnecting said termina1s,said fuse link being fastened to saidi fuse linkterminal member and restraining the movement-thereof when said fuse link is unfused.

'7. A fuse switchcomprising insulating means. supporting relatively spaced'terminals including an outwardly extending lower terminalof resili ient conducting material, a fuse tube movablebetween open andclosed positions, a fuse link' within said tube electrically connecting, said terminals, a swingably movable fuse link terminal member at the lower end of said 'tube,,a swingably movable load contact member extending upwardly from the lower end of said tube in engagement with said outwardly extending; lower terminal when said fuse isin the closed position and said fuse link is unfused, said swingably movable load contact member'having a'portion thereof positioned inthe path of movement of said fuse link terminal member for engagement by the latter after it has moved a predetermined distance along said path, and means biasing said fuselink terminal so that it engages and initiates movement of said contact member away from ducting material, aflfuse tube movable between open and closed positions,a fuse link within said tube electrically connecting said terminals, a swingably movable fuse link terminal member and a swingably movable lowercontact member pivotally mounted at the lower end of said tube for rotation about a common axis, said lower contact member extending upwardly from the lower end of said tube and engaging said lower terminal when said fuse tube is in the closed position and said fuse link is'unfused, said swingably movable lower contact member having a relatively stationary portion thereof positioned in the path of movement of said fuse link terminal member for engagement by thelatter only after it has'moved a predetermined distance along said path whereby terminal-disengaging movement of said lower contact member i initiated, and means biasing said fuse link terminal in a direction to engage and move said contact member away from said outwardly extending lower terminal, said fuse link being fastened to said fuse link terminal member and restraining the movement thereof when said fuse link is unfused.

9. In a circuit interrupter, a terminal memher, a contact member movable to and'away from said terminal member to respectively close and open the circuit, arelatively movable fuse link terminal member arranged to move a predetermined distance while said contact member' remains unmoved and to strike, and thereby initiate movement of said contact member to open the circuit, and 'a fuse link'fastened to said' fuse link terminal member and restraining the movement thereof. i Y

10. In a circuit interrupter, a terminal'memher, a contact member movable to and away from said terminal member to respectively close and open the circuit, a spring-pressed movable fuse link terminal member arranged to strike said contact member following an unimpeded movement of said fuse link terminal member which occurs while said contact member remains unmoved and over a predetermined path suificiently long to impart thereto substantial momentum,

and a fuse link serially connected in said circuit and-fastened to said fuse link terminal for tion about a common axis, said lower contact contact member having a relatively stationary portion thereof positioned in the path of movement of said fuse link terminal member for engagement by the latter after it has moved a predetermined distance along said path, said relasaid outwardly extending lower terminal only 7 after moving said predetermined distance, vsaid fuse link being fastened to said fuse link terminal member andrestraining the movement thereof when said fuse link is unfused. I d

8.-A.fusel switch comprising insulating means supporting spaced terminals including an cut wardly extending lower terminal of, resilienticontively stationary portion remaining unmoved while said fuse'link terminal member moves oversaid predetermined distance and moving only supporting spaced terminals including an outwardly extending lower terminal of resilient material, a fuse tube movable between open and closed positions, a fuse link within said tube electrically connecting said terminals, a swingably movable fuse link terminal member and a swingably movable lower contact member pivotally mounted at the lower end of said tube for rotation about a common axis, said lower contact member extending upwardly from its pivotal mounting and engaging said lower terminal when said fuse tube is in the closed position and said fuse link is unfused, said swingably movable lower contact member having a relatively stationary portion thereof positioned in the path of movement of said fuse link terminal member for engagement by the latter only after it has moved a predetermined distance along said path, said relatively stationary portion remaining unmoved while said fuse link terminal member moves over said predetermined distance and moving only after being struck by said fuse link terminal member, said fuse link having the upper end thereof fastened to said tube and the lower end fastened to said fuse link terminal member, and means biasing said fuse link terminal member in a direction to engage and move said contact member away from said outwardly extending lower terminal.

13. In a fuse switch, a fuse tube, a supporting member rigidly secured to said tube, .a terminal, and a contact member arranged for movement between an engaged and a disengaged p sition with respect to said terminal, a fuse link terminal member pivotally mounted on said supporting member and so constructed and arranged as to strike and thereby actuate said contact member from the engaged to the disengaged position following a predetermined movement of said fuse link terminal, said contact member remaining unmoved while'said predetermined movement occurs and moving only after being struck by said fuse link terminal member, and biasing means urging and a fuse link restraining said fus link terminal member.

14. In a fuse switch, spaced terminals, means supporting a fuse tube in series circuit relation with said terminals, a fus link terminal member and a terminal-engaging contact member pivotally mounted on said fuse tube for rotation about a common axis, a fuse link within said tube having its ends fastened respectively to said fuse tube and to said fuse link terminal member, said fuse link terminal member extending across said fuse tube and downwardlyalong said fuse tube 1 when said fuse link is unfused, and means responsive to the rupture of said fuse link for actuating said terminal-engaging contact member to the disengaged position following a predetermined movement of said fuse link terminal member, the said predetermined movement rotating said fuse link terminal member so that the downwardly extending portion of the latter swings outwardly away from the fuse tube to an indicating position.

15. In a fuse switch, spaced terminals, means supporting a fuse tube in series circuit relation with said terminals, said fuse tube having mounted thereon for limited rotation about a common axis and in the same direction a fuse link terminal member and a terminal-engaging contact member, said fuse link terminal member extending laterally across said fuse tube and normally downwardly therealong, a fuse link within said tube normally electrically connecting said terminals, said fuse link having its ends fastened respectively to said tube and to said fuse link terminal member, resilient means biasing said fuse link terminal member for rotation in a direction to tension said fuse link, and means responsive to a predetermined movement of said fuse link terminal member under the influence of said resilient means and following the rupture of said fuse link for actuating said contact-engaging member to the disengaged position, the said predetermined movement rotating said fuse link terminal member so that the normally downwardly extending portion thereof moves outwardly away from the fuse tube to an indicating position.

16. A fuse switch comprising an insulator, spaced upper and lower terminals mounted thereon, and a connecting member movable from open to closed position pivotally mounted at its lower end, said connecting member including a lower terminal contact member arranged to engage the lower terminal when the connecting member is in the closed position, said lower terminal being resilient and arranged to react on said connecting member in a direction to maintain the latter in the closed position.

17. A fuse switch comprising an insulator, spaced upper and lower terminals mounted thereon, a connecting member supported on said insulator and movable from the open to the closed position, means for pivotally mounting said connecting member at an elevation below said lower terminal and in lateral spaced relationship with said insulator, said connecting member having a portion thereof extending upwardly to said load terminal, and said load terminal being resilient and arranged to press said portion downwardly between the pivotal mounting of said connecting member and said insulator, whereby said connecting member is maintained in the closed position.

1-8. A fuse switch comprising an insulator, spaced terminals thereon including an upper terminal at the upper end thereof and a resilient outwardly extending lower terminal, a connecting member movable from the open to the closed position supported on said insulator, and means for pivotally mounting said connecting member at an elevation below said lower terminal and in lateral spaced relationship with said insulator, said connecting member having a portion thereof extending upwardly in resilient engagement with said outwardly extending lower terminal in a vertical plane which is positioned between the insulator and the pivotal mounting of the connecting member, whereby the reaction of said resilient outwardly extending lower terminal on said connecting member is in a direction to rotate th latter toward the closed position.

RALPH R. PITTMAN. CARROLL H. WALSH. 

